22 USC 2705---Recognizes a full validity U.S. passport as proof of the bearer's U.S. citizenship.

8 USC 1104(a)(3)---Makes the Secretary of State responsible for "the determination of [the] nationality of a person not in the United States."

8 USC 1481(b)--States that the burden of showing loss of U.S. citizenship is on the party so claiming and such a claim must be established by a preponderance of the evidence.

22 CFR 53.1 et seq.---Requires, with certain exceptions, that U.S. citizens enter and depart the United States on U.S. passports.

22 CFR 50.40(a)---Establishes an administrative presumption that, absent an assertion to the contrary, a U.S. citizen who naturalizes in a foreign country, takes a routine oath of allegiance, or accepts non-policy level employment with a foreign state intends to retain his/her U.S. citizenship.